Conventional semiconductor laser devices are disclosed, for example, in Patent Literature 1, Patent Literature 2, and Patent Literature 3.
Disclosed in Patent Literature 1 is a semiconductor laser module which has a semiconductor laser bar with two surfaces sandwiched between metal sub-mounts. The sub-mounts can be made of Mo, W, Cu, Cu—W alloy, Cu—Mo alloy, SiC, or AlN. Each of the sub-mounts has a thickness of 50 to 200 μm. In this semiconductor laser device, the semiconductor laser module is mounted onto a liquid-cooled heat sink. This makes it possible to correct warpage of the semiconductor laser bar.
Disclosed in Patent Literature 2 is a semiconductor laser device which has a semiconductor laser bar mounted on a heat sink and which has a reinforcement member affixed onto the same surface as the surface of the heat sink on which the semiconductor laser bar is mounted. The reinforcement member is made of a material having a low linear expansion coefficient. The reinforcement member is made of a material selected from the group consisting of Cu, Al, Ni, W, Mo, Fe, Cr, Co, and Bi.
Disclosed in Patent Literature 3 is a semiconductor laser device which has a liquid-cooled heat sink coated with a resin layer and a semiconductor laser bar mounted thereon. This Literature discloses a structure which is capable of providing an enhanced cooling efficiency and preventing corrosion and water leakage.